Update: Nearly fully contained - Grand Fire in San Bernardino County at 90%

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Updated: 2:52 p.m. May 16

First discovered: 3 days ago, 7:13 p.m. May 13

Initial location: Grand Avenue and Pleasant Hill Drive, Chino Hills, San Bernardino County, Calif.

Fire unit: Cal Fire San Bernardino Unit in Unified Command with Chino Valley Fire

Fire type: Wildfire

Fire name: Grand Fire

Grand Fire initially started 7:13 p.m. May 13 at Grand Avenue and Pleasant Hill Drive, Chino Hills in San Bernardino County, California.

Since its discovery three days ago, it has burned 36 acres. 90% of the fire was brought under containment by a crew of 60 firefighters as of Saturday afternoon. The cause of the wildfire is linked to a vehicle.

The fire is fought by six engines and two hand crews. According to Cal Fire, "Numerous firefighting air tankers from throughout the State are flying fire suppression missions as conditions allow."

Fire containment

Interpreting what 90% containment means

Containment indicates what percentage of the fire perimeter has been surrounded by a control line. In this case, it means that 90% of the wildfire is contained from spreading, while 10% is still uncontrolled.

Containment is part of a larger plan for managing a wildfire. It is normally expressed as a percentage and it refers to how much of the fire perimeter has been surrounded/enclosed by a control line that firefighters create. The containment percentage indicates a certain level of control, but it doesn't always correlate to safety level. Also, it's important to note that containment doesn't mean a fire is out.

How is containment measured?

The incident's central command constantly receives progress reports from firefighters on the ground. As the fireline is constructed, inspected or reinforced, mappers record those details to adjust the containment percentage. The percentage tells the public how much of the fire perimeter is believed to not go beyond the control lines.

Source: Cal Fire

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This story was originally published May 16, 2026 at 3:17 PM.